SailNet Community banner

1 - 20 of 20 Posts

·
Registered
Joined
·
625 Posts
Discussion Starter #1 (Edited)
1968 B32 keel/CB # 26.

I am in the process of rebuilding my Centerboard cable and pulleys in the trunk and would like some input.

System failed this year (two months ago). 25 years ago the same thing happened, or at least I think the same thing happened. My dad had the yard do the work at that time. Dad has passed on a few years ago. I did not see what was involved at that time for the repair, but was told the cable came off the shielded pulley in the trunk and jammed. I'm sure, at that time, the cable was replaced and pulley fixed or replaced. The system is and has held up well in 25 years from the last repair. I use it every time I go sailing. This year when I was raising the CB the pulley let go again, I was 90% sure, and it got very hard to raise, so I did not force it. Left it in the 1/3 way down position for the rest of the year and let the yard know of the issue to take care when hauling. They hauled it this week. I got to look at it yesterday. CB is still there, yay! That’s a good start. I was able to look up in the trunk and did see the sheave sitting loose on top of the board. I am lucky I did not lose it. I proceeded to take it apart. Hoping I can do this repair without removing the CB. I disconnected the cable from the winch, removed the pulley, block and wood mounting base off to expose the top of the cable tube that runs through the cabin. Unscrewing the tube from the access plate on the top of the trunk, it was way too easy to get free. Tube looks like chrome covered brass. I will get it chromed again. I took the service plate off the top of the trunk, and that too went way too easy. I found two pulleys attached to the underside of the plate. Both pulleys mounts will need replacing. One of the pulleys had fallen off and was wedged on top of the CB in the trunk and was starting to show signs of damaging the trunk walls. Good thing I did not try to force the CB up. I will post pictures of this repair.

I have a few questions if anyone has done this work:

1. Does anyone know of any other thread covering this repair? I searched the forum but could not find any that covered this size CB or configuration.

2. Looks like the access plate and pulley supports are made of brass, and pulleys and pulley pins are made of stainless steel. How do I identify what the plate is made of? Edit/Answer:I was able to find a metal color chart to identify the metal. Looking like Navel Brass ($96.00) and I'm going with 3" Fiberglass reinforced Nylon Sheaves ($16.52) and Naval Brass pivot pins and no retaining pins, no room for them to fall out, the trunk is only 1-1/2" wide.

3. Damage looks like indifferent metal corrosion damage (Galvanic Corrosion). See pictures. I was wondering if the yard, when fixing this issue last time (25 years ago), changed the original sheaves and pins that were maybe brass as well with the SS ones. I researched and can get in brass. Any down side to using brass? The deck pulleys for this system are brass. http://www.fastenal.com/content/feds/pdf/Article - Corrosion.pdf Edit/answer: Using all brass parts.

4. Anyone know someone that can fix the brass supports for me for a reasonable cost? They will need to be cut off and new ones wielded on. Someone in the North East USA please. Edit/answer: I did all this work myself. I was able to order the Naval Brass C464 parts cut to size, $65.86. Order Brass, Nickel Silver Angle, Ball, Hex, Metal Pack, Pipe, Round, Sheet, Square, Tube Alloys , , 230, 260, 330, 360, 385, 770, 792, Brass in Small Quantities at OnlineMetals.com and will be electric brazing, ($22.50) (50,000 lbs psi) this myself.:)

5. What can I use instead of SS wire rope for cable? Although what I have seen in other threads is people have had issues with the cable breaking. The cable I have now after 25 years is not showing any signs of letting go, but I have not been able to get a good look at the cable connection to the CB. Next time I go to the boat I will get pics of this connection. Edit/Answer: 20'x3/16" Stainless Steel 316 7x16 wire rope ($40.00) with an oval Copper nickel sleeve swage fitting ($5.00), 3700 lbs BK and 760 lb WL rated. I am estimating the, 16" at the widest part and 6'-6" long fiberglass, CB weighs 60 to 80 lbs and has two 8" round led or zinc counter weights towards the bottom end imbedded in the glass and a 1" naval brass pivot pin. I was going to use Amsteel, but I was not keen on the UV issue, my cable is exposed to UVs and I liked the 25 years I got out of the last SS one. Details can be found in plans I am putting together to document this setup.

6. Can I replace this cable without removing the CB? I will try to get access to it by raising it by hand and blocking it up and access this from the access port on top. As you will see in the pics that the sheaves and supports are about 4” tall and the slot is only like 2” wide. Not sure if that is enough space. Or I could do the whole repair, button it up and leave a snake wire in place of the new cable, wait for the yard to lift boat for launching in the spring, swing the CB all the way down. I think I will have access to the connection at that time. I would prefer to not do the latter or remove the board. Edit/Ansewr: Yes, cable can be replaced in the all the way up position (with the access plate removed), and the all the way down position.:)

7. Looks like the yard made their own rubber gasket for the access plate, I will do the same. What material should I use? And what caulking to seal rubber to bronze and rubber to fiberglass? 5200? Edit/answer: I will be using 3M 4200 (2 tubes @$16.. each, used 1 and 1/2 tubes), with rubber gasket material from Rubber Sheet Roll (general purpose rubber "Genpurp" 0.25"x12"x36" $18.37+sh). Made my own gasket out of this. See final pics.

Thanks in advance for your help.

Edit: Looks like the entire repair will cost just under $200. And I should never have a sheave issue again.






If you want CAD files or PDF: https://drive.google.com/file/d/0B_ddc5Lj8s0WOWJBY1I4VnVza0E/edit?usp=sharing
https://drive.google.com/file/d/0B_ddc5Lj8s0Wd0JjZUV0dElOVlU/edit?usp=sharing
 

·
Registered
Joined
·
372 Posts
I don't have a lot of answers but I would question the bronze supports. Why would you not go ahead and have stainless steel ones made instead of bronze? Seems like it'd be a lot easier to find someone to do that work. and then you don't have the galvanic corrosion to worry about. As far as immersed SS, there are lots of bits that get immersed and as you said the pulleys and everything else looks fine.
 

·
Tartan 27' owner
Joined
·
5,242 Posts
The guys at your local friendly prop shop work with bronze every day. I bet they could help you out with any bronze fabrication you might want. I'd prefer bronze in my bilge areas over stainless steel any day.

I'd ditch the wire rope for a high tech line like Amsteel - which ain't cheap but is really strong. If you switch to regular line you may need to replace all the sheaves with ones compatible with rope instead of wire; sheaves for wire have a "V" shaped groove while rope sheaves have a "U" shape.

Please do everyone a favor and do not use 5200 for any part of this repair. There are many types of sealing/bedding caulks that could be used instead: 4200, Boatlife, 3M ... Butyl tape.

I like your idea of getting all your sheaves squared away, threading your new line and waiting until the spring to attach the new pennant to the center board while the boat is in the slings (if that is what you meant).

Good luck.
 

·
Registered
Joined
·
625 Posts
Discussion Starter #4
I don't have a lot of answers but I would question the bronze supports. Why would you not go ahead and have stainless steel ones made instead of bronze? Seems like it'd be a lot easier to find someone to do that work. and then you don't have the galvanic corrosion to worry about. As far as immersed SS, there are lots of bits that get immersed and as you said the pulleys and everything else looks fine.
The access plate the sheaves and blocks are mounted on is bronze, I believe.
 

·
Registered
Joined
·
625 Posts
Discussion Starter #5 (Edited)
The guys at your local friendly prop shop work with bronze every day. I bet they could help you out with any bronze fabrication you might want. I'd prefer bronze in my bilge areas over stainless steel any day.
Thank you and agree on the bronze.

I'd ditch the wire rope for a high tech line like Amsteel - which ain't cheap but is really strong. If you switch to regular line you may need to replace all the sheaves with ones compatible with rope instead of wire; sheaves for wire have a "V" shaped groove while rope sheaves have a "U" shape.
I will look into Amsteel. Sheaves are the U style. Even the mast top sheaves were the U, I had no issues converting the old wire rope Halyards to rope. Can you see any issues with Amsteel and connection to the CB? And now that I think of it I would have to change the winch that is made to except wire rope. I did read somewhere someone was thinking of using the Amsteel and splicing with wire rope in the riser tube. I assume the two can be spliced?

Please do everyone a favor and do not use 5200 for any part of this repair. There are many types of sealing/bedding caulks that could be used instead: 4200, Boatlife, 3M ... Butyl tape.
Okay, no 5200. Do I need the rubber gasket or just caulk? Butyl tape for under waterline? Edit: After research... no Butyl tape under water line. Looks like 4200 without gasket is what I will use.

I like your idea of getting all your sheaves squared away, threading your new line and waiting until the spring to attach the new pennant to the center board while the boat is in the slings (if that is what you meant).
I am hoping to be able to replace the cable from the top access. I am not sure I can get the access I need with the CB all the way down. Would hate to wait then not be able to replace it and hold up launching. I am hoping to find someone that knows if that is an option (having access with CB all the way down). I know the yard removed it the last time it was repaired, I can see where they patched the hull.

Thanks for your input
 

·
Tartan 27' owner
Joined
·
5,242 Posts
Please do look up Amsteel line at defender or your favorite chandlery. The breaking strength of this stuff is incredibly high with very low stretch - which is why it can be used for standing rigging too.
I'm not sure why you'd need to splice Amsteel to wire rope. The entire run could be in Amsteel which would allow you to attach to the center board with a bowline knot, in a pinch.
There is probably some sort of "d" ring or shackle on the top edge of the center board that the wire rope connected to. Hopefully that is still in good shape but you might try to be prepared to replace it when you can access it.

I believe that NOAA uses a form of Butyl to seal some of their submersible research buoys. For sealing the top of your center board trunk I think it would work fine since you have the top bolted down as well. When applied correctly Butyl will flatten out and fill the voids under the cover with pressure from bolts holding the top down.
Another idea is to use some rubber from a bicycle tire inner tube to make a gasket.

If you used 5200 then someone would be cursing your name the next time they try to open up the trunk top. It might even be you!
 

·
Registered
Joined
·
625 Posts
Discussion Starter #7
I'm not sure why you'd need to splice Amsteel to wire rope. The entire run could be in Amsteel which would allow you to attach to the center board with a bowline knot, in a pinch.
The winch for lifting the CB is designed to except the 1/4" wire rope with a set screw. The cable is continuously wrapped on the drum and holds the CB in any position. Rope will not work with this winch. And I would like to keep the boat looking and original as possible, within reason.
 

·
Registered
Joined
·
625 Posts
Discussion Starter #8
What do you all think about me adding a zinc pencil or two with threaded NPT brass cap? And grounding the plate to the engine? Plate looks thick enough to drill and tap, or I could have a matching female nipple welded on top of plate to accommodate new zinc. These zincs could be replaced easy each year.
 

·
Registered
Joined
·
372 Posts
If you are going to stick with bronze a zinc and grounding it might not be a bad idea, but you would want to research that since adding a zinc is not a cure all. If you go bronze you might want to look at getting bronze for the pulleys and pins as well.

Depending on how flush the surfaces are you could probably avoid having a rubber gasket at all. I would avoid butyl tape since that is not what it is designed for. Nothing wrong with 4200 or 5200. 5200 is a bear to remove but it is not impossible. 4200 or something else would allow you to remove it easier and it seems like this might be something yo should be inspecting every few years.

I know people seem keen on replacing stainless steel wire with Amsteel but in this case I think it is a solution in search of a problem. Breaking strength is not an issue with either material but what would be the advantage here? Up top you could argue lighter rig, easier field servicablility, etc. For this application all I see is a material that does not resist chafe as well as stainless steel wire and is in a place that it can't be easily inspected end to end.
 

·
Registered
Joined
·
625 Posts
Discussion Starter #11
I'm wondering if barnacles need light to grow? The only explication I can come up with as to why there is no growth higher the 3" up in the CB trunk. The trunk is open to the air through the CB cable tube that is attached to the top of the trunk access plate, runs straight up through the cabin and through the cabin top. Trunk is always full of water and cable pipe has water in it up 18".
 

·
Registered
Joined
·
625 Posts
Discussion Starter #12
I am still considering using Amsteel. The Blue 1/4" has a load rating of 8600 lbs. And would fit my winch. And I am having a small issue with replacing the cable at the CB connection. Today I jacked the CB up in the trunk as high as it would go to see if I can get the connection. Looks like I will be able to cut the old one off, but not sure I can get the crimping tool in to reconnect.

I thought I saw somewhere that the Amsteel could be knotted (tied to the CB to connect). I have pictures of all this. Coming soon...
 

·
Registered
Joined
·
625 Posts
Discussion Starter #13
Anyone have any info on using Amsteel under salt water? Rot? If Amsteel can be used, I understand it takes a sharp bend better than wire rope, and if it can be used under water, I would prefer to use it. Looks like what I have heard from others this is the point of cable failure and low and behold I found my cable about to break in that spot as shown in this picture
 

·
Registered
Joined
·
625 Posts
Discussion Starter #14 (Edited)
First pass at cleaning up the plate...


Looks more like brass than bronze to me.

The nut for attaching the cable tube is definitely brass.
 

·
Registered
Joined
·
372 Posts
Where you show the cable chafe is it where it connects to the centerboard? Still wouldn't think amsteel would handle chafe better than wire but in any case use a thimble.
 

·
Registered
Joined
·
625 Posts
Discussion Starter #16
Where you show the cable chafe is it where it connects to the centerboard? Still wouldn't think amsteel would handle chafe better than wire but in any case use a thimble.
Yes, centerboard connection. Looking from the top of the trunk down.

I'm not understanding chafe of the Amsteel? Cable moves a total of 12" to lower CB all the way down. And real slow movement. And only will ajust it once or twice a sail. Sometimes, as I am starting to loose my mind, I forget to raise it up when at dockside. I seldom use it all the way down. most the time only 1/3 down works well. I understand the Amsteel is very stiff at first, but will soften with use.

Still wouldn't think amsteel would handle chafe better than wire but in any case use a thimble.
I don't think a "thimble" would last but a few years. And not sure I have room for one, sheave is the stopping point on top of the CB. I think the cable crimp you see in that pic rides up on the sheave or damn close to it. I can measure to see how much room there is after the sheave is fixed. Can't tell till it is fixed.
 

·
Registered
Joined
·
57 Posts
Delta-T,

Thanks for the info on your repair-in-progress, I have not found much info on repairing the centerboard cable systems on Bristols (or any other boats). Yours is very detailed and thorough, thanks.

I am in the middle of repairing the centerboard cable on my Bristol 29.9. The system is similar but most of the components are fabricated in fiberglass instead of bronze (except the shivs themselves) and the two shivs are in separate "knuckles" that are connected by fiberglass pipes, one directly above the centerboard connection, the other just behind the engine. The system is controlled by a winch mounted inside the starboard cockpit locker, with the handle inserted through the locker wall in the cockpit.

Anyway, my repairs have required me to cut open the shiv knuckle above the centerboard and the pipe just at the exit of the second knuckle by the engine. I had to do this in order to get the new cable run through. I tried various other "fishing" methods to pass a line through the system without cutting but could not prevent the fishing line from coming off the shivs and jamming thus preventing the new cable from being pulled through.

I have decided to go the Amsteel route for the new cable, using 1/4 inch rope. I spliced an eye into it at the centerboard end. My understanding is the only weakness of amsteel is lack of UV resistance, which is not an issue for this job. Rotting should not be a problem with this rope.

I do not have the same kind of damage you show in your pictures, just a replacement cable is all I need for now. However I can see potential for having to replace/repair the bronze shafts the shivs run on in the future.

I should have the whole system back together and sealed up by the end of this week, and the boat back in the water mid-April. I'll report back on how it is working with the amsteel cable.

Best of luck.
 

·
Registered
Joined
·
625 Posts
Discussion Starter #19
Just finished this project today...

Access plate with new blocks:


Gasket, sheaves and blocks primed with 2000E barrier coat, ready to install:


The trunk matching flange and 26 studs (3 missing), need lots of TLC and prep to make acceptable for the access plate. Access plate, gasket, blocks, sheaves and cable installed with 3M 4200:


Sanded the chrome off the brass cable tube, polished and lacquered:


Cable up to the deck:


Now on to the normal spring upkeep. We get wet 5/1/14. I'm hoping to work being there for that.
 
1 - 20 of 20 Posts
Top